A flag is a piece of fabric (most often rectangular or quadrilateral) with a distinctive design that is used as a symbol, as a signaling device, or as decoration. The term flag is also used to refer to the graphic design employed, and flags have since evolved into a general tool for rudimentary signalling and identification, especially in environments where communication is similarly challenging (such as the maritime environment where semaphore is used). National flags are potent patriotic symbols with varied wide-ranging interpretations, often including strong military associations due to their original and ongoing military uses. Flags are also used in messaging, advertising, or for other decorative purposes. The study of flags is known as vexillology, from the Latin word vexillum, meaning flag or banner.

Due to the use of flags by military units, 'flag' is also used as the name of some military units. A flag (Arabic: لواء) is equivalent to a brigade in Arab countries, and in Spain, a flag (Spanish: bandera) is a battalion-equivalent in the Spanish Legion.

During the peak of the age of sail, beginning in the early 17th century, it was customary (and later a legal requirement) for ships to carry flags designating their nationality;[1] these flags eventually evolved into the national flags and maritime flags of today. Flags also became the preferred means of communications at sea, resulting in various systems of flag signals; see, International maritime signal flags.

Use of flags outside of military or naval context begins only with the rise of nationalist sentiment by the end of the 18th century; the earliest national flags date to that period, and during the 19th century it became common for every sovereign state to introduce a national flag.[citation needed]

One of the most popular uses of a flag is to symbolize a nation or country. Some national flags have been particularly inspirational to other nations, countries, or subnational entities in the design of their own flags. Some prominent examples include:

The flag of the Netherlands is the oldest tricolour. Its three colours of red, white and blue go back to Charlemagne's time, the 9th century. The coastal region of what today is the Netherlands was then known for its cloth in these colours. Maps from the early 16th century already put flags in these colours next to this region, like Texeira's map of 1520. A century before that, during the 15th century, the three colours were mentioned as the coastal signals for this area, with the 3 bands straight or diagonal, single or doubled. As state flag it first appeared around 1572 as the Prince's Flag in orange–white–blue. Soon the more famous red–white–blue began appearing, becoming the prevalent version from around 1630. Orange made a come back during the civil war of the late 18th century, signifying the orangist or pro-stadtholder party. During WW2 the pro-nazi NSB used it. Any symbolism has been added later to the three colours, although the orange comes from the House of Orange-Nassau. Surprisingly, this use of orange comes from Nassau, which today uses orange-blue, not from Orange, which today uses red-blue. However, the usual way to show the link with the House of Orange-Nassau is the orange pennant above the red-white-blue.
It's said that the Dutch Tricolour has inspired[citation needed] many flags but most notably those of Russia, New York City, and South Africa (the 1928–94 flag as well the current flag). As the probable inspiration for the Russian flag, it is the source too for the Pan-Slavic colours red, white and blue, adopted by many Slavic states and peoples as their symbols. Examples: Slovakia, Serbia, and Slovenia.

A civil flag is a version of the national flag that is flown by civilians on non-government installations or craft. The use of civil flags was more common in the past, in order to denote buildings or ships that were not manned by the military. In some countries the civil flag is the same as the war flag or state flag, but without the coat of arms, such as in the case of Spain, and in others it's an alteration of the war flag.

Other countries' armed forces (such as those of the United States or Switzerland) use their standard national flag. The Philippines' armed forces may use their standard national flag, but during times of war the flag is turned upside down. Bulgaria's flag is also turned upside down during times of war. These are also considered war flags, though the terminology only applies to the flag's military usage.

Large versions of the war flag flown on the warships of countries' navies are known as battle ensigns. In war waving a white flag is a banner of truce or surrender.

Four distinctive African flags currently in the collection of the National Maritime Museum in Britain were flown in action by Itsekiri ships under the control of Nana Olomu during conflict in the late 19th century. One is the flag generally known as the Benin flag and one is referred to as Nana Olomu's flag.[3]

Flags are flown on boats to indicate the country of registration of the boat.

Flags are particularly important at sea, where they can mean the difference between life and death, and consequently where the rules and regulations for the flying of flags are strictly enforced. A national flag flown at sea is known as an ensign. A courteous, peaceable merchant ship or yacht customarily flies its ensign (in the usual ensign position), together with the flag of whatever nation it is currently visiting at the mast (known as a courtesy flag). To fly one's ensign alone in foreign waters, a foreign port or in the face of a foreign warship traditionally indicates a willingness to fight, with cannon, for the right to do so. As of 2009, this custom is still taken seriously by many naval and port authorities and is readily enforced in many parts of the world by boarding, confiscation and other civil penalties.

In some countries yacht ensigns are different from merchant ensigns in order to signal that the yacht is not carrying cargo that requires a customs declaration. Carrying commercial cargo on a boat with a yacht ensign is deemed to be smuggling in many jurisdictions. There is a system of international maritime signal flags for numerals and letters of the alphabet. Each flag or pennant has a specific meaning when flown individually. As well, semaphore flags can be used to communicate on an ad hoc basis from ship to ship over short distances. Traditionally, a vessel flying under the courtesy flag of a specific nation, regardless of the vessel's country of registry, is considered to be operating under the law of her 'host' nation.

Flags are usually rectangular in shape (often in the ratio 2:3, 1:2, or 3:5), but may be of any shape or size that is practical for flying, including square, triangular, or swallow tailed. A more unusual flag shape is that of the flag of Nepal, which is in the shape of two stacked triangles. Other unusual flag shapes include the flag of Ohio and the flag of Tampa.

Many flags are dyed through and through to be inexpensive to manufacture, such that the reverse side is the mirror image of the obverse (front) side, generally the side displayed when the flag is flying from the observer's point of view from left, the side of the pole, to right. This presents two possibilities:

If not, the obverse and reverse will present two variants of the same design, one with the hoist on the left (usually considered the obverse side, the other with the hoist on the right (usually considered the reverse side of the flag). This is very common and usually not disturbing if there is no text in the design.

Some complex flag designs are not intended for through and through implementation, requiring separate obverse and reverse sides if made correctly. In these cases there is a design element (usually text) which is not symmetric and should be read in the same direction, regardless of whether the hoist is to the viewer's left or right. These cases can be divided into two types:

The same (asymmetric) design may be duplicated on both sides. Such flags can be manufactured by creating two identical through and through flags and then sewing them back to back, though this can affect the resulting combination's responsiveness to the wind. Depictions of such flags may be marked with the symbol , indicating the reverse is congruent to (rather than a mirror image of) the obverse.

Common designs on flags include crosses, stripes, and divisions of the surface, or field, into bands or quarters—patterns and principles mainly derived from heraldry. A heraldic coat of arms may also be flown as a banner of arms, as is done on both the state flag of Maryland and the flag of Kiribati.

The de jureflag of Libya under Muammar Gaddafi, which consisted of a rectangular field of green, was for a long period the only national flag using a single colour and no design or insignia. However, other historical states have also used flags without designs or insignia, such as the Soviet Republic of Hungary, whose flag was a plain field of red.

Colours are normally described with common names, such as "red", but may be further specified using colourimetry.

The largest flag flown from a flagpole worldwide, according to Guinness World Records, is the flag of Mexico flown in Piedras Negras, Mexico. This flag was about 2,058 m2 (22,150 sq ft).[4] The largest flag ever made was the flag of Qatar; the flag, which measures at 101,978 m2 (1,097,680 sq ft), was completed in December 2013 in Doha.[5]

The general parts of a flag are: canton—the upper inner section of the flag; field or ground—the entire flag except the canton, and the field and hoist ends; fly end—the furthest edge from the hoist end; and hoist end—the edge used to attach the flag to the hoist.[6]

Vertical flags are sometimes used in lieu of the standard horizontal flag in central and eastern Europe, particularly in the German-speaking countries. This practice came about because the relatively brisk wind needed to display horizontal flags is not common in these countries.[7]

The standard horizontal flag (no. 1 in the preceding illustration) is nonetheless the form most often used even in these countries.[8]

The vertical flag (German: Hochformatflagge or Knatterflagge; no. 2) is a vertical form of the standard flag. The flag's design may remain unchanged (No. 2a) or it may change, e.g. by changing horizontal stripes to vertical ones (no. 2b). If the flag carries an emblem, it may remain centered or may be shifted slightly upwards.[7][9]

The vertical flag for hoisting from a beam (German: Auslegerflagge or Galgenflagge; no. 3) is additionally attached to a horizontal beam, ensuring that it is fully displayed even if there is no wind.[7][10]

The vertical flag for hoisting from a horizontal pole (German: Hängeflagge; no. 4) is hoisted from a horizontal pole, normally attached to a building. The topmost stripe on the horizontal version of the flag faces away from the building.[7][11]

The vertical flag for hoisting from a crossbar or banner (German: Bannerflagge; no. 5) is firmly attached to a horizontal crossbar from which it is hoisted, either by a vertical pole (no. 5a) or a horizontal one (no. 5b). The topmost stripe on the horizontal version of the flag normally faces to the left.[7][12]

Flags can play many different roles in religion. In Buddhism, prayer flags are used, usually in sets of five differently coloured flags. Many national flags and other flags include religious symbols such as the cross, the crescent, or a reference to a patron saint. Flags are also adopted by religious groups and flags such as the Jain flag and the Christian flag are used to represent a whole religion.

As languages rarely have a flag designed to represent them,[13] it is a common but unofficial practice to use national flags to identify them. The practice is deprecated[14] because it is often considered insulting[15] and because flags tend to evoke feelings other than the intended meaning. Examples of such use include:

representing language skills of an individual, like a staff member of a company

displaying available languages on a multilingual website or software.

Though this can be done in an uncontroversial manner in some cases, this can easily lead to some problems for certain languages:

In this second case, common solutions include symbolising these languages by:

the flag of the country where the language originated

the flag of the country having the largest number of native speakers

a mixed flag of the both (when this is not the same)

the flag of the country most identified with that language in a specific region (e.g. Portuguese Language: Flag of Portugal in Europe and Flag of Brazil in South America). A Portugal-Brazil mixed flag, usually divided diagonally, is also a possibility.

Because of their ease of signalling and identification, flags are often used in sports.

In association football, linesmen carry small flags along the touch lines. They use the flags to indicate to the referee potential infringements of the laws, or who is entitled to possession of the ball that has gone out of the field of play, or, most famously, raising the flag to indicate an offside offence. Officials called touch judges use flags for similar purposes in both codes of rugby.

In American and Canadian football, referees use penalty flags to indicate that a foul has been committed in game play. The phrase used for such an indication is flag on the play. The flag itself is a small, weighted handkerchief, tossed on the field at the approximate point of the infraction; the intent is usually to sort out the details after the current play from scrimmage has concluded. In American football, the flag is usually yellow; in Canadian football, it is usually orange. In the National Football League, coaches also use red challenge flags to indicate that they wish to contest a ruling on the field.

In yacht racing, flags are used to communicate information from the race committee boat to the racers. Different flags hoisted from the committee boat may communicate a false start, changes in the course, a cancelled race, or other important information. Racing boats themselves may also use flags to symbolize a protest or distress. The flags are often part of the nautical alphabetic system of International maritime signal flags, in which 26 different flags designate the 26 letters of the Latin alphabet.

In auto and motorcycle racing, racing flags are used to communicate with drivers. Most famously, a checkered flag of black and white squares indicates the end of the race, and victory for the leader. A yellow flag is used to indicate caution requiring slow speed and a red flag requires racers to stop immediately. A black flag is used to indicate penalties.

In addition, fans of almost all sports wave flags in the stands to indicate their support for the participants. Many sports teams have their own flags, and, in individual sports, fans will indicate their support for a player by waving the flag of his or her home country.

For safety, dive flags indicate the locations of underwater scuba divers or that diving operations are being conducted in the vicinity.

In water sports such as Wakeboarding and Water-Skiing, an orange flag is held in between runs to indicate someone is in the water.

In golf, the hole is almost always marked with a flag. The flagpole is designed to fit centered within the base of the hole and is removable. Many courses will use colour-coded flags to determine a hole location at the front, middle or rear of the green. However colour-coded flags are not used in the professional tours. (A rare example of a golf course that does not use flags to mark the hole is the East Course of Merion Golf Club, which instead uses flagpoles topped by wicker baskets.)

Flag poles with flags of all shapes and sizes are used by marching bands, drum corps, and winter guard teams use flags as a method of visual enhancement in performances.

Some of these political flags have become national flags, such as the red flag of the Soviet Union and national socialist banners for Nazi Germany. The present Flag of Portugal is based on what had been the political flag of the Portuguese Republican Party previous to the 5 October 1910 revolution which brought this party to power.

Flags are often representative of an individual's affinity or allegiance to a country, team or business and can be presented in various ways. A popular trend that has surfaced revolves around the idea of the 'mobile' flag in which an individual displays their particular flag of choice on their vehicle. These items are commonly referred to as car flags and are usually manufactured from high strength polyester material and are attached to a vehicle via a polypropylene pole and clip window attachment.

In Australia, Canada, New Zealand, the Philippines, and the United Kingdom a pair of red/yellow flags is used to mark the limits of the bathing area on a beach, usually guarded by surf lifesavers. If the beach is closed, the poles of the flags are crossed. The flags are coloured with a red triangle and a yellow triangle making a rectangular flag, or a red rectangle over a yellow rectangle. On many Australian beaches there is a slight variation with beach condition signaling. A red flag signifies a closed beach (in the UK also other dangers), yellow signifies strong current or difficult swimming conditions, and green represents a beach safe for general swimming. In Ireland, a red and yellow flag indicates that it is safe to swim; a red flag that it is unsafe; and no flag indicates that there are no lifeguards on duty. Blue flags may also be used away from the yellow-red lifesaver area to designate a zone for surfboarding and other small, non-motorised watercraft.

Railways use a number of coloured flags. When used as wayside signals they usually use the following meanings (exact meanings are set by the individual railroad company):

red = stop

yellow = proceed with care

green or white = proceed.

a flag of any colour waved vigorously means stop

a blue flag on the side of a locomotive means that it should not be moved because someone is working on it (or on the train attached to it). A blue flag on a track means that nothing on that track should be moved. The flag can only be removed by the person or group that placed it. In the railway dominated steel industry this principle of "blue flag and tag" was extended to all operations at Bethlehem Steel, Lackawanna, NY. If a man went inside a large machine or worked on an electrical circuit for example, his blue flag and tag was sacrosanct.[16] The "Lock Out/Tag Out" practice is similar and now used in other industries to comply with safety regulations.

At night, the flags are replaced with lanterns showing the same colours.

Flags displayed on the front of a moving locomotive are an acceptable replacement for classification lights and usually have the following meanings (exact meanings are set by the individual railroad company):

white = extra (not on the timetable)

green = another section following

red = last section

Additionally, a railroad brakeman will typically carry a red flag to make his or her hand signals more visible to the engineer. Railway signals are a development of railway flags.[17]

A flagpole, flagmast, flagstaff, or staff can be a simple support made of wood or metal. If it is taller than can be easily reached to raise the flag, a cord is used, looping around a pulley at the top of the pole with the ends tied at the bottom. The flag is fixed to one lower end of the cord, and is then raised by pulling on the other end. The cord is then tightened and tied to the pole at the bottom. The pole is usually topped by a flat plate or ball called a "truck" (originally meant to keep a wooden pole from splitting) or a finial in a more complex shape. Very high flagpoles may require more complex support structures than a simple pole, such as a guyed mast.

The tallest flagpole in the United Kingdom from 1959 until 2013 stood in Kew Gardens. It was made from a Canadian Douglas-fir tree and was 68.5 m (225 ft) in height.[22]

The current tallest flagpole in the United States (and the tallest containing an American flag) is a 400 ft (120 m) pole completed near Memorial Day 2014 and custom-made with a large 11 feet (3.4 m) base in concrete by wind turbine manufacturer Broadwind Energy, which is situated on the north side of the Acuity Insurance headquarters campus along Interstate 43 in Sheboygan, Wisconsin and is visible from Cedar Grove. The pole will hold a 220-pound flag for pleasant conditions and a thicker 350-pound flag for harsh weather.[23] Acuity had made three separate attempts in the 2000s at the tallest flagpole which were all removed due to collapses or wind-swaying, following the example of a nearby Perkins location which had put up a flag visible on their property from the WI 28 exit.

Flagpoles can be designed in one piece with a taper (typically a steel taper or a Greek entasis taper),[24] or be made from multiple pieces to make them able to expand. In the United States, ANSI/NAAMM guide specification FP-1001-97 covers the engineering design of metal flagpoles to ensure safety.

Hoisting the flag is the act of raising the flag on the flagpole. Raising or lowering flags, especially national flags, usually involves ceremonies and certain sets of rules, depending on the country, and usually involve the performance of a national anthem.

A flag-raising squad is a group of people, usually troops, cadets, or students, that marches in and brings the flags for the flag-hoisting ceremony. Flag-hoisting ceremonies involving flag-raising squads can be simple or elaborate, involving large numbers of squads. Elaborate flag-hoisting ceremonies are usually performed on national holidays.

Semaphore is a form of communication that utilizes flags. The signalling is performed by an individual using two flags (or lighted wands), the positions of the flags indicating a symbol. The person who holds the flags is known as the signalman. This form of communication is primarily used by naval signallers. This technique of signalling was adopted in the early 19th century and is still used in various forms today.

The colours of the flags can also be used to communicate. For example; a white flag means, among other things, surrender or peace, a red flag can be used as a warning signal, and a black flag can mean war, or determination to defeat enemies.

Orientation of a flag is also used for communication, though the practice is rarely used given modern communication systems. Raising a flag upside-down was indicative that the raising force controlled that particular area, but that it was in severe distress.[citation needed]

When blown by the wind, flags are subject to wave-like motions that grow in amplitude along the length of the flag. This is sometimes ascribed to the flag pole giving vortex shedding, however flags that are held by lanyards also can be seen to flap.

^National Flag -The official website of Denmark. An earlier use of the white cross on red is attested by an armorial (Netherlands) of 1370-1386. In later monastic tradition, the Danneborg made its first, miraculous appearance at the Battle of Lyndanisse on 15 June 1219.